The medicinal plants are used in traditional treatments to cure variety of diseases for thousands of year. The aim of this study was to identify such plants with antimicrobial efficacy for controlling some pathogenic Escherichia coli strains. The locally available plants viz., garlic (Allium sativum), turmeric (Curcuma longa), crown flower (Calotropis gigentica), and Indian lilac (Azadirachta indica) were selected for the study. Ethanol extracts of these plants at two different doses (500- and 1000µg/disc) were examined against pathogenic E. coli strains using disc diffusion method as compared with standard kanamycin (30μg/disc.) Antibacterial activity was determined by measuring growth inhibition zones of E. coli strains. E. coli 119-EAE was more sensitive to all experimented extracts of medicinal plants except crown flower at the rate of 1000 μg/disc than other three strains. At the both concentration, the ethanol mixed extracts of crown flower and Indian lilac was most effective towards all E. coli strains. These extracts demonstrated the highest antibacterial activity against E. coli 119-EAE inhibiting its growth (21mm zone of diameter) at the dose of 1000μg/disc compared to standard antibiotic, kanamycin followed by Indian lilac and turmeric. The extracts of garlic exhibited the lowest inhibitory responses to all test organisms apart from E. coli 119-EAE strains. Furthermore, for in vivo challenge test of shrimps (Penaeus monodon), by using ethanolic mixed extracts of crown flower and Indian lilac the lowest average bacterial load of E. coli was observed to be 2.11*10⁴ CFU/g at the concentration of 1000µg/µl in muscle of shrimp reducing from 3.09*10⁴ CFU/g found without applying extracts as control. These results suggested that there was strong antagonistic activity of ethanolic mixed extract of crown flower and Indian lilac against the strain of E. coli and it can be used in favor of proper fish health management controlling the risk of contamination from pathogenic E. coli in shrimp as important source of drugs.